


Boiling Point

by cagestark



Category: Marvel Cinematic Universe
Genre: Adult Peter Parker, Alpha!Peter, Alpha/Beta/Omega Dynamics, Anal Sex, Just Because of the Consent Issues involved in Heats, Knotting, M/M, Mating Cycles/In Heat, Mildly Dubious Consent, omega!Tony, peter is 18+
Language: English
Status: Completed
Published: 2019-07-28
Updated: 2019-07-28
Packaged: 2020-07-24 18:17:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,832
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20018902
Author URL: https://archiveofourown.org/users/cagestark/pseuds/cagestark
Summary: Alpha!Peter is displaying inappropriate behavior. Accidentally. Probably. But Omega!Tony is pretty cool with it. Until the pot boils over.





	Boiling Point

**Author's Note:**

> this is my own version of ABO, so some things might be a little different. First crack at a fic of this kind

The thing is, the kid is too polite.

Peter is freshly eighteen when he moves into the tower and begins interning for Tony, spending every last moment Avenging and patrolling and attending online classes. Being thirty years older than the kid, a part of him assumes that he should take on the role of a cantankerous old man complaining about the boorish youth. His knees have certainly taken it upon themselves to method act, protesting hours spent cross-legged on the floor. His hair has obviously been visiting wardrobe and makeup without his notice, because there are more gray hairs there than he remembers there being last year, last season, last _month_.

All this to say that Tony is getting older, and it is no secret that the younger generations are fucking irritating. _Disrespectful_ , he’d say, channeling Howard or Jarvis through that internal Ouija board that keeps coming back no matter how many times he throws it out. And alright, it’s part of their rite of passage. Find him a generation who doesn’t annoy their elders and he’d eat Cap’s shield.

The one exception: Peter.

The kid has sweetness in his DNA. Authenticity clings to his red blood cells which explains why every bone in his body is genuine and kind. The respect he shows the Avengers is nearly comical—would be, if it didn’t drive Tony up the walls for other reasons. He is firm and gentle, thoughtful and conscientious. There are no valid complaints to be had about him.

The kid, if anything, is _too_ polite.

Which means that he can’t possibly be doing this on purpose.

Peter presenting as an alpha shocked Tony to the core, and he wasn’t alone. “I’ve had him pegged as an omega since he was in diapers, Tony,” May had whispered to him while they watched Peter having his blood drawn by Bruce inside the Hulk-proof enclosure beneath the ground at Stark Tower. Judging by how Peter’s face flushes red, he can hear through the glass.

“A lot people had _me_ pegged as an alpha,” Tony responds, maybe a little too coldly. But maybe it hits a little too close to home—children having their designations determined for them at such a young age. How much of Peter’s upbringing had influenced his disposition? Had he been groomed to be an omega even despite his biology? The thought makes Tony sick. He knows how that feels. He _knows_. “This doesn’t change anything about him. He’s still Peter.”

But it did change things.

Because now they are playing this game together, and either Peter is a better bluffer than Tony ever anticipated, or the kid genuinely doesn’t know what he’s doing to the older man.

It starts the first day Peter returns to his work in the lab after his rut. They have been putting in hours together working on a new AI, one Peter has affectionately dubbed Saturday, no matter how many times Tony tells him that the key to a good name is all in the _acronym)._ Since it is Peter’s first effort to make an artificial intelligence, Tony is letting him lead. He is bent over the lab table examining a microchip the size of his thumbnail, miniature soldering iron clutched between in his fingers when the door to the lab opens.

He whirls around on the stool, beaming. Peter is dressed in his old Midtown High sweatshirt, the collar of his dress shirt blooming around his neck. His hair is dark from a shower, wet curls clinging to his forehead. He looks—good. Healthy. Strong. _Fertile_.

They smell each other for the first time.

It’s not Tony’s right to tell anyone to wear scent blockers, though he ingests his own via pill form twice a day, showers with them, has them mixed into the sterilization stations at lab’s exits so he can clean his hands and neutralize any happy-angsty scents that were brought about during the day’s tinkering. Because it’s a _polite_ thing to do. Alphas and omegas are very sensitive to smells. Polite alphas will wear blockers to avoid overwhelming omegas or antagonizing other alphas in public—and when it comes to omegas, scent blockers are like protection, like the nano-tech suit he goes nowhere without. If no one can smell Tony, they can’t look at him like a piece of meat, lust over him, come on to him _when all he’s trying to do is walk down the fucking street._

The kid is not wearing blockers. Before he presented, Peter had the blandly neutral scent of a beta, and he would have been incapable of scenting Tony. Peter smells of something fond. It takes Tony only a moment to place it: the mahogany of the bookshelves in his childhood home, the lemon-basil scent that would cling to Jarvis after days spent in the kitchen.

He sees Peter’s nostrils flair, surely trying to take in a scent that for all intents and purposes, he shouldn’t be able to smell. But by the way his eyes go hooded, throat bobbing, he can. The boy’s mouth opens, literally mouths the word _wow_. Tony feels remarkably like a rabbit caught in a dog’s gaze.

Tony burns himself. “Fucking— _fuck_!” He drops the soldering iron and it barely misses the microchip.

“Mr. Stark, are you okay?”

Peter comes over to examine the burn, a dark, flushed pink, the skin already raw and shiny. The smell comes with him, each of the boy’s emotions playing out like a symphony for his nose: concern, comfort, anxiety. And yeah, arousal.

Tony pulls away before their skin can touch, jamming his hands into the gloves that he should have been wearing from the start. “Fine,” he says. “Don’t worry about it.” 

Peter becomes—distracting. At best. Arousing at worst. Days spent in the lab under Tony’s tutelage are filled with emotions for the young, enthusiastic boy: joy when he solves a problem, frustration when he can’t, the soft melancholic scent of rotting wood on days when his smile is muted and his eyes seem far away. Tony is too receptive to him. More than once, he’s found himself opening his mouth, desperate to ask _for the love of God, Pete, will you take a shower? Will you wear something, anything, to come between your scent and my nose?_ But the kid doesn’t deserve that, and Tony isn’t sure he could stand the embarrassed, insecure scent he’d give off after being confronted. The need to _comfort_ might be too strong to overpower.

Tony does his very best to maintain a professional relationship, but Peter seems determined to cross every boundary.

Next comes the scenting. To be fair: maybe he doesn’t know how incredibly personal it is. Tony knows that it’s common in schools to separate kids by designation and teach them only the information absolutely pertinent to them. Maybe growing up small and thin and soft hearted, pegged O’ from birth, they didn’t teach him what it means when an alpha scents someone who they aren’t related to.

Tony himself doesn’t know what it means when Peter does it. Maybe _Peter_ doesn’t even know, maybe it’s just an itch that needs scratched, and he knows that scenting Tony can scratch it. Some things are just that innocent. But on his dark days when Tony is hunched over at the lab table, back and eyes aching from working through the night, all it takes is Peter brushing by. His steps will stutter just beyond Tony’s shoulders. He inhales—now Tony is trained like one of Pavlov’s dogs, and the relief, the arousal, it often comes right then, even on just the _inhale_ —and then Peter’s forehead will loll forward, soft hair and skin nuzzling at the scent gland on Tony’s neck until their scents are mixed. Until Tony’s body is soft and pliant (except for his cock, which is hard and throbbing).

Then Peter moves on like nothing happened.

_What the fuck_ , Tony sometimes mouths, keeping his eyes on the tablet in front of him, terrified to turn and acknowledge what the boy just did.

It might not be so bad if they weren’t so fucking compatible. Yeah, he can admit it. Tony had spent weeks agonizing about that after the kid first brought his scent down into the lab, he’s come to terms, thanks. It’s a biological fact, one he remembers any time he takes in a whiff of mahogany and lemon-basil. God, he didn’t think a smell could be so comforting and arousing all at once. It makes him ache, someplace in his chest where the arc reactor used to sit, and somewhere lower, deep in his pelvis where he should have grown children, if he’d been a decent omega. If he hadn’t spent so long trying to pretend to be an alpha, frying his biology, cooking his ovaries right to medium-well-done, AKA infertility.

What use would Peter have for him? Tony is old, past safe childbearing years even if he wasn’t barren. Alphas want legacies, they want homemakers, they want everything Howard worked so hard to empty Tony of. Far too often he finds himself maudlin and thinking such thoughts before the futility of them strikes him. His attractiveness is a non-issue; he is determined that he and Peter will never come together that way.

As it is, the scent blockers Tony takes, while being ultra-effective, aren’t as effective for a pair—not a pair. No, they’re not a _pair_. Just two friendly friends, mentor and mentee, platonic _hi there Mr. Stark how are you doing_ goodness, no knots involved. God. He should not be thinking about the kid’s knot—anyway, the blockers aren’t as effective for people who are as compatible as Peter and Tony are. They are his last defense, and he often burns through them before the afternoon hits, body working overtime to make his scent potent again so that he might have a chance to attract the virile alpha across the room. It’s embarrassing, smelling so badly of pining omega that he can smell himself in the enclosed space of the elevator.

Like he is right now.

Although, it isn’t the elevator. It’s the bathroom.

Tony grabs the hand towels off of the rack and stuffs them at the bottom of the door where the crack is, desperate to keep his own smell in and Peter’s smell out. Then he crawls into the bathtub there and draws the curtain shut. As if that’s going to help.

He looks to the ceiling, wondering why a deity he doesn’t even believe in seems to be punishing him like this. Inside his pants, his cock is aching, and he can’t help but to press the heel of his hand against it, exhaling in the brief relief it gives. Lifting his wrist to his nose he breaths deep and can’t stop the groan that passes his lips. He smells like Peter, their scents combining, lemon and sugar to make lemonade, so sweet his mouth waters and his teeth ache.

When Peter arrived in the lab just moments before, he’d brought with him the scent of fury: scorched earth, and something sadder. His eyes were red from tears, lips pressed thin together. Tony watched him, paralyzed, as he tried three different times to enter his access code to the lab before FRIDAY showed mercy and let him in. Then as soon as there was nothing between them, it was like two oppositely charged magnets coming together.

They collided. Tony’s arms wrapped around him and Peter’s nose buried in that spot between his neck and shoulder, inhaling and exhaling fire on Tony’s exposed skin. Peter babbles away, lips brushing his skin, something about an argument with Ned and MJ, both sides feeling neglected and wronged, long overdue issues just now bubbling to the surface, he’d imagine. He can barely focus on what the boy is saying. It feels like there’s an invisible hand on the back of his neck, tilting him into the perfect position for his alpha to scent and find comfort in him. Tony holds him until all the anger and hurt and helplessness have seeped out of him.

_What the fuck,_ Tony mouths to the ceiling. One of these days, he’s going to ask FRIDAY to create a montage of his WTF moments so that he might literally have concrete footage of how weird his life is.

Then one of Peter’s hands drifts up like he is going to cup Tony’s shoulder, but instead he firmly presses his thumb into the gland there and it’s like Thor has sent a bolt of lightning down. Tony’s entire body jerks and melts, every bone in his body relaxing for his alpha except for the one in his pants, and _speaking of_ , Peter whimpers and shifts and there is no mistaking an alpha’s cock. There just isn’t. It’s veritably huge and hard and how many years has it been since he’s had an alpha inside him, since he’s been knotted—

The scents around them change, thick with arousal. It takes him that long to realize that Peter’s heightened emotional sensitivity _might_ have a biological cause.

He is going into a rut.

“Mr. Stark,” Peter slurs, hips shifting. “You smell _sooo_ good.”

It takes herculean effort to separate their bodies. The sheer heat and pheromones that Peter is throwing off are tangible even when he’s resolutely breathing through his mouth. He must be a sight: eyes wild and terrified, cock stiff, sprinting bow-legged to the bathroom so that he could get just a moment—just a moment to calm himself down and use his brain.

It’s going…about as well as can be expected, Tony thinks, desperately fisting his cock in the bathtub. If he could just rub one out, maybe it will bleed some of the fire from his veins. There is a gentle knocking at the door and Peter’s muffled voice, but Tony can barely hear it. He’s so close, building up to an orgasm so quickly that it should be shameful, but at least there is no one here to see. Wrist pressed to his nose, he inhales Peter’s scent like a man coming up from water, desperate for air. His balls are drawn up tight, stomach twisted into knots—and still he doesn’t cum.

“Mr. Stark, are you alright? Are you hurt?” Peter’s voice is raised, worried. Tony realizes that he has been whimpering, surely loud enough for the genetically enhanced boy to hear.

The pain inside him rises up but never crests, just rests there, aching in his gut. Cramping. Curiously, he reaches down past the petite testicles, down—

He’s wet. Soaked. The touch of his finger nearly brings him to ecstasy. This is what he needs, something inside of him, filling that emptiness that is so acute it aches. One finger isn’t enough. His hole is already loose, taking two easily.

The door breaks down. _I’m in heat_ , Tony thinks numbly listening to wood splinter and hinges break. Maybe there was a slow build up that he missed, but it burned away in an instant in the face of this alpha. _That is why Peter went into rut. Because of me._ He barely has time to shove his cock back into his pants. For a moment, after Peter wrenches back the shower curtain Tony feels like a woman out of the old bodice rippers his mother used to keep in her bedside drawer. The ones with helpless omegas ravished by alphas who were driven mad by their scents, alphas who couldn’t have stopped their urges even if they wanted to.

The look Peter gives him is certainly aroused enough. He is hard in his jeans, a bulge that looks impossibly huge compared to Tony’s own. Peter’s chest rises and falls so rapidly that the older man is worried for his health. Those dark eyes scan Tony from head to toe and then the boy collapses, knees striking the tiled floor, groaning. He crawls to the bathtub and rests his feverish cheeks against the lip of the tub, mouth open and panting.

“ _Mr. Stark_.” The voice is absolutely wrecked.

It is pure restraint as a result of his years of experience that keeps him from rolling onto his hands and knees to present for this boy, this wet-behind-the-ears alpha who has barely started his second rut and probably never popped a knot in his life.

“Mr. Stark I don’t feel so good,” groans Peter.

Even burning up, cramping, shaking, Tony reaches out to pet at Peter’s head. He hopes to offer comfort, but the boy snatches his hand out of the air in a bruising grip. Then he draws it to his mouth and presses in the fingers that were just inside Tony’s sopping hole. The boy’s tongue slips between the fingers, searching every crevice for more slick, groaning even as he licks the palm tasting only heart-love-life lines. “Mr. Stark,” Peter pants, trying again for words. “Can I have you? _Please_. Let me have you.”

“Yes,” Tony gasps.

They come together clumsily. It takes a moment for them to realize that Tony is trying to crawl out of the tub while Peter is trying to crawl in. They end up outside of it on the tiled floor, Tony spread out underneath the young alpha. Peter sheds his shirt and there should be violins, there should be mood lighting and a spotlight because the kid is fucking built. He almost has as many abs as fingers, so lithe and strong. He reminds Tony of spider silk, thin and so strong.

“Undress,” Peter says lowly, helping Tony to sit up so that he might pull off his shirt. Yeah, Tony isn’t 18 years old with genetically enhanced muscles but he likes to think he does okay. Peter’s eyes roll, palms flat on Tony’s pecs to drag down and down, over the scarring where the arc reactor used to be, scraping at the chest hairs. It melts the omega’s brain, primal parts of him purring. His body is satisfying to his mate, even if he is older and grayer and harder than any omega has a right to be. “God, you’re so—Jesus you’re hot Mr. Stark.”

“Knot me,” Tony groans. His hips are thrusting up into the hard cradle of Peter’s pelvis. His cock is throbbing, leaking, but it is nothing compared to the emptiness inside of him. The room is small and filled with so many potent scents that he can barely keep his eyes open. All of his senses are consumed by Peter, by what he’s doing with Peter. “Come on, kid. It hurts.”

Peter goes feral at the thought. He tears at their clothes, ribbons of jean and cotton, tennis shoes nudged off of feet. When he is naked as the day he was born, the fever in Tony seems to reach its boiling point. The kid is sculpted; it’s indecent. If there was any doubt he was meant to be an alpha, his cock disputes it. Tony, who has had plenty of fulfilling sexual experiences with people of all genders and designations, is still intimidated. Aroused. Anxious. He knows that his biology has prepared him for this. His body is made to take cocks of that size, but what if it doesn’t? What if he displeases this alpha, displeases Peter?

A hand comes to rest on his shoulder, thumb pressing into that tender part of his neck that has his legs jolting. “Easy,” Peter says, and Tony’s entire body relaxes. That voice drains all the fear and anxiety out of him, Novocain for the soul. Why was he worrying? His head is pleasantly fuzzy like with the buzz of a few strong drinks. Underneath it all is the ache in his cock, the emptiness inside him, but he does not beg. Does not squirm. Because unbearably tender, Peter assures: “I’ll take care of you.”

The tiles under his palms and knees are cold on his feverish skin when he turns over. He lets his back bow to appease the ache inside him until he is presenting fully, cheek pressed against the floor. The sounds Peter makes behind him are wrecked as he folds himself over the omega beneath him, mouth hotly over the skin at the nape of his neck. It makes all the hairs on his body stand on edge—god the only thing better than mating with alpha is bonding with this alpha, _bite, bite, please_ —

“Can’t,” Peter groans. “Can’t bite you. You don’t mean that.”

Tony bucks the boy off until Peter is sitting back on his haunches, cock obscene between his legs, looking more like a confused pup than an assertive alpha. Tony bares his teeth even in the face of his instincts which recoil just at the idea. “I thought you knew what I needed,” he goads.

Peter’s eyes harden. Maybe this polite young man defers to him on most things, but _not this thing._ He fists a hand in Tony’s hair and wrenches him up until their naked bodies are plastered together from knee to neck. Teeth brush his neck again and it’s like touching a live wire. If he’d jerked any harder, he might have broken skin. As it is, Peter just holds him there, bite firm and bordering on painful until all the fight goes out of him. The boy guides him back down, body lax like all the bones are gone. One hand drifts up and back to run over where the alpha’s teeth were, desperate to feel the indentations.

“Didn’t break skin,” Peter promises, like Tony doesn’t already know. No broken skin, but close. Close enough to have him pliant and purring, the fever in his skin giving him the briefest respite. Then Peter’s fingers dance downward to where the omega is wet and hot and so empty it hurts. Just the brush of fingertips, the promise of pleasure, has Tony groaning into the tiled floor.

Gently, Peter presses in. Attuned to the alpha’s senses, he hears the younger man’s breath catch, turn high and breathy. A second finger joins the first and yes, that’s better, so much better than the gaping emptiness. By the third finger, Tony feels like he could cum from this alone, even if Peter has done nothing but skim his fingers over that spot inside him that’s so good it aches.

Peter hushes him, a hand planted over that fading mark on the back of Tony’s neck. His other hand grips his cock, notching the head where Tony needs it most. The omega takes the first half before he feels full, sated even, but then there is more. Peter makes the rawest noises, and Tony laments not facing him, not being able to see his expression. He can imagine it: the eyes squeezed shut, mouth open, head back. But then there is more cock inside him than he thought was possible, and it burns everything else from his mind. The only thing that exists is that cock, anchoring him to this reality. He can feel the flared base of the alpha’s cock already puffing, desperate to knot.

Content that his cock isn’t going to split Tony in half—though it certainly feels like it from the other side of things—Peter sets a brutal pace. The finesse his fingers might have lacked is overshadowed by his cock which probably couldn’t miss Tony’s prostate if it tried. All he can do is take it, fingers scrabbling to find purchase on the slick floor, body singing, prepared to burn out at any moment.

“ _To-ny_ ,” whines Peter, drawing the word out obscenely. The next word is softer, said through teeth: “ _Omega_.”

“Alpha,” Tony gasps. “Harder—more. Come on. Need it, need your knot—”

“Then take it,” Peter cries. “Take it! God, you feel so good, you’re perfect, perfect—”

Tony cums, cock spurting onto the tiled floor. Every muscles clenches, cramping, spasming as his orgasm goes on and on, spurred on by Peter’s cock. Tony can’t even take it enough breath to scream, just gapes, cheek pressed to the cool floor. He can feel Peter’s own end coming, the knot growing, the sounds he makes becoming louder and less inhibited.

When Peter finally cums, he howls, crying out the way a man might if he’d just been stabbed only he’s the one stabbing Tony, stabbing him with his cock, forcing the knot past the rim and Tony doesn’t know if he can take it, there is brief pain cresting and then—it’s like it all goes white. His first orgasm was nothing compared to this. This would be painful, if it weren’t so good, if it weren’t exactly what he needed. It’s so much deeper than when he cums from his cock; in a way that feels so external. But this is inside him, deep in his womb, his entire body and being rejoicing at the alpha inside him loading him with sperm. Every spasm of his body is matched a heartbeat later by the cock inside him.

The come-down is slow. Having lost his strength ages ago, Tony is prostrate on the floor, knees and back aching. Above him is a firm, warm weight. The breaths are too ragged for Peter to be sleeping. Still, there is no speaking. Not until the knot inside him deflates and Peter draws back, cum and slick slipping out from inside of Tony.

When he manages to get up on his hands an knees, reaching out to use the sink to brace himself to stand (trying hard not to slip in all the bodily fluids), he sees that Peter is sitting back on his haunches, face buried in his hands, shaking with tears.

Tony nearly flinches at the sight. His heart pounds—alpha, hurting.

“Peter? Pete? God, what is it? Are you—”

“I’m so sorry,” Peter wails.

“Wh—what the hell are you sorry for?”

Peter can’t even answer, he’s so distraught. Tony isn’t good at this. It’s safe to say that most emotional situations have him withdrawing, and hastily. But this is Peter: the young man he’s had a soft spot for even years before the attraction arrived. So instead he lowers himself back down and sits next to the boy, drawing him in. Peter buries his face in Tony’s neck, scenting and scenting. It isn’t hard to exude comfort and warmth, not when he has the young alpha in his arms. Peter’s tears slow and then stop.

Heart in his throat, Tony asks: “What that—not good for you, kid?”

When Peter pulls away, his face is twisted with confusion. “What are you talking about? That—it was—God, Mr. Stark. I’m going to be thinking about that for the rest of my life, probably.”

The omega inside him purrs. “Thanks for the ego boost.”

Peter sighs, wiping at his face. “That’s just so not how I wanted it to happen. When you’re, when you’re in heat you can’t technically consent. You ran from me and I literally—oh shoot, Mr. Stark, I broke down your door.”

“About that—it’s coming out of your paycheck.”

“I’m not being paid, I’m an intern—"

“You— _what_? You’re not being paid? That doesn’t sound—”

“Can we, like, talk about my pay later?”

Tony’s mouth clicks shut. He nods.

“I just,” Peter sighs, relaxed with his head in the crook of Tony’s neck. They’re both naked, sweat cooling rapidly, but their bodies pressed together are more than enough to keep them warm. “All that effort I put in trying to attract you, trying to treat you right, like an alpha is supposed to treat an omega—then I went and broke your door.”

“Jesus,” Tony mutters. “I should have known you’re too smart not to know what you’ve been doing. Scenting me like I’m going out of style.”

“You’ll never go out of style Mr. Stark,” Peter assures. “I thought I was being subtle. It never seemed to _work_. Then I got worried that maybe you just weren’t interested. But I can _smell_ you.”

“I’m interested,” Tony says into the younger man’s hair. “Trust me. Interested is putting it lightly. Not to mention, I’m a pretty creative guy. I could have probably stopped you if I wasn’t interested.”

“Even if you could, it’s not right for me to, to just—consent is important!”

“You’re goddamn right it is,” Tony says. He draws Peter’s chin up so they can meet eyes, and even bloodshot and wet, Peter’s are still warm and sincere and painfully adorable. “So, while I’m of sane mind and in between waves, let’s just go ahead and say I’m giving you consent. Enthusiastically. Deal?”

It’s Peter’s turn to melt and then purr, a low growling in his chest, looking like the spider who caught the fly, only more charming and with far less legs thank god. He mouths at Tony’s neck, kissing the gland there to make him shiver, and when he speaks Tony can feel the brush of his lips moving against his skin: “ _Deal_.”

**Author's Note:**

> Comments and criticisms more than welcome. Highly encouraged, actually. Also come see me on tumblr: cagestark


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